The Rhine Rhone Eastern Branch Phase 1 is a 137km 320km/h HSR line between Dijon and Mulhouse (adjacent to Basel in Switzerland) in the East of France. The public railway authority RFF, now SNCF Réseau, decided to tender three lots divided geographically for the services of the Engineer (EPCM): Egis was awarded Lot B, thanks to its value engineering concepts proposed during the bid and implemented during the project. Our competence in earthworks and structures as well as contractual innovation was key to our project delivery.
As the Engineer for the early works and main civil works, we performed the preliminary and detailed design, tendering period and contract negotiations assistance, shop drawing approval, construction supervision, commissioning, management of the contactor’s defects liability period and project closeout. The main figures of Lot B is as follows: 57km, 12 Million m3 of cut, 9 Million m3 of fill, 76 standard structures, and 6 viaducts (between 89 and 792m in length).
To select the Engineer, SNCF Réseau based its evaluation on the competitors performing a Value Engineering of the previous conceptual design to reduce the project’s CAPEX. This exercise consisted of analysis and submittal of design concepts including drawings and calculations, to justify the cost savings. Egis submitted and realized over 30 such VE design improvements in its proposal. As an example, we slightly modified both the HSR and road alignments to standardize bridge spans and crossing angle, thereby making it much easier to precast and transport bridge elements.
A second VE example was to reduce the cross-sectional area of the tunnel that is at the top of a pass between two valleys. In hilly terrain, HSR trains operate similar to a roller coaster in that the maximum speed is at the bottom of vertical curves and with a slower speed at the crests. We calculated the reduced speed at the top of the crest in the tunnel and consequently proposed a corresponding reduced tunnel cross-section area.
A third VE example was that from aerial photography, we identified a zone of uneven settlement from ancient mines and therefore proposed to modify the alignment to avoid it. This VE indirectly reduced the CAPEX through the reduction of risk.
Turning to the execution of the design, Lot B consisted of 7 different underground conditions resulting in complex earthworks. Some of the materials changed their mechanical properties when exposed to water and air, creating difficulties for reuse. Therefore to balance the cuts and fills required a complex technical solution. Laboratory analysis was performed on all 7 of the material types, with the identification of specific material to be transformed through a treatment process and reuse for track formation subgrade. Other materials which had poor mechanical and chemical properties were placed within the “core” of a fill, which in turn was encapsulated to isolate it from water intrusion.
The complex geotechnical approach in the reuse of the material resulted in major cost savings and minimum environmental impact. If we had not applied this approach, the project would have consumed the equivalent of 10 years of production from the region’s quarries, thereby creating a material shortage for the region’s other infrastructure projects.
The Lot B alignment included a number of viaducts and other major structures. Egis modified the alignment to better flow with the natural topography thereby reducing the overall length of structures by 40%. These modifications included the viaducts in the valleys of Quenoche, Linotte and Corcelles. Besides reduction in the cost of the structures and optimization of earthworks, the execution of the design was closely tied to the process of obtaining consents from local authorities. This integration of the consents process with the design execution was key to being successful on both fronts. As an example, for the Corcelles valley and inhabitants within, the conceptual design consisted of a 1.5km viaduct passing 500m from the village. Egis was able to drop it down and reduce its length to 800m thereby lowering visual impact. It should be noted that by having a HSR with a lower environmental impact, the Corcelles village has been able to prosper with its population having grown since the HSR construction.
Our EPCM contract had bonus/penalty incentives clause tied to the final construction outcome. We succeeded in hitting our target, for schedule as well as CAPEX.
Our contract was comprehensive, covering all rail systems as well. Although the project was divided up into three engineering lots, it was apparent that the only way to have efficient construction of the rail systems would be for construction lots to be transversal across the engineering lots. For example, to have a single contractor lay track instead of three contractors working from three separate railheads. But having multiple Engineers directing a contractor through a single contract is not allowed under French law.
Consequently, through contractual creativity we created a consortium beneath the three engineering contracts to jointly perform the services of the Engineer for the rail systems. By this manner it was possible to have a single construction lot per each system (supply of track material, track laying, OCS, traction power, signalling, communications, etc.) and a single railhead. The consortium’s services included:
Similar to the civil works, the rail systems portion of our contract also had an incentives clause that we successfully complied with.